package org.cleverframe.common.utils;

import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.net.URLEncoder;

import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.binary.Hex;
import org.apache.commons.lang3.StringEscapeUtils;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * 封装各种格式的编码解码工具类<br>
 * 1.Commons-Codec的 hex/base64编码 <br>
 * 2.自制的base62 编码 <br>
 * 3.Commons-Lang的xml/html escape<br>
 * 4.JDK提供的URLEncoder<br>
 * 
 * @author LiZW
 * @version 2015年6月19日 下午3:49:24
 */
public class Encodes
{
    /** 日志对象 */
    private final static Logger logger = LoggerFactory.getLogger(Encodes.class);
    
	private static final String DEFAULT_URL_ENCODING = "UTF-8";
	private static final char[] BASE62 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz".toCharArray();

	/**
	 * Hex编码.
	 */
	public static String encodeHex(byte[] input)
	{
		return Hex.encodeHexString(input);
	}

	/**
	 * Hex解码.
	 */
	public static byte[] decodeHex(String input)
	{
		try
		{
			return Hex.decodeHex(input.toCharArray());
		}
		catch (DecoderException e)
		{
			throw Exceptions.unchecked(e);
		}
	}
	
    /**
     * 判断字符串是否是Hex编码，传入空值或null返回true<br>
     * <pre>
     * ""           --->    true
     * null         --->    true
     * "0164abf"    --->    true
     * "asdfwae"    --->    false
     * </pre>
     */
    public static boolean isHexcode(String input)
    {
        if(StringUtils.isBlank(input))
        {
            return true;
        }
        boolean flag = true;
        for (char c : input.toCharArray())
        {
            if ((c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F'))
            {

            }
            else
            {
                flag = false;
                break;
            }
        }
        return flag;
    }

	/**
	 * Base64编码.
	 */
	public static String encodeBase64(byte[] input)
	{
		return Base64.encodeBase64String(input);
	}

	/**
	 * Base64编码, URL安全(将Base64中的URL非法字符'+'和'/'转为'-'和'_', 见RFC3548).
	 */
	public static String encodeUrlSafeBase64(byte[] input)
	{
		return Base64.encodeBase64URLSafeString(input);
	}

	/**
	 * Base64解码.
	 */
	public static byte[] decodeBase64(String input)
	{
		return Base64.decodeBase64(input);
	}

	/**
	 * Base62编码。
	 */
	public static String encodeBase62(byte[] input)
	{
		char[] chars = new char[input.length];
		for (int i = 0; i < input.length; i++)
		{
			chars[i] = BASE62[(input[i] & 0xFF) % BASE62.length];
		}
		return new String(chars);
	}

	/**
	 * Html 转码.
	 */
	public static String escapeHtml(String html)
	{
		return StringEscapeUtils.escapeHtml4(html);
	}

	/**
	 * Html 解码.
	 */
	public static String unescapeHtml(String htmlEscaped)
	{
		return StringEscapeUtils.unescapeHtml4(htmlEscaped);
	}

	/**
	 * Xml 转码.
	 */
	public static String escapeXml(String xml)
	{
		return StringEscapeUtils.escapeXml11(xml);
	}

	/**
	 * Xml 解码.
	 */
	public static String unescapeXml(String xmlEscaped)
	{
		return StringEscapeUtils.unescapeXml(xmlEscaped);
	}

	/**
	 * URL 编码, Encode默认为UTF-8.
	 */
	public static String urlEncode(String part)
	{
		try
		{
			return URLEncoder.encode(part, DEFAULT_URL_ENCODING);
		}
		catch (UnsupportedEncodingException e)
		{
			throw Exceptions.unchecked(e);
		}
	}

	/**
	 * URL 解码, Encode默认为UTF-8.
	 */
	public static String urlDecode(String part)
	{
		try
		{
			return URLDecoder.decode(part, DEFAULT_URL_ENCODING);
		}
		catch (UnsupportedEncodingException e)
		{
			throw Exceptions.unchecked(e);
		}
	}
	
	/**
	 * 处理浏览器下载文件的文件编码问题
	 * @param userAgent 浏览器标识:request.getHeader("User-Agent")
	 * @param fileName 文件名称
	 * @return
	 */
    public static String browserDownloadFileName(String userAgent, String fileName)
    {
        try
        {
            if (userAgent.toUpperCase().indexOf("MSIE") > 0 || userAgent.toUpperCase().indexOf("LIKE GECKO") > 0)
            {
                fileName = URLEncoder.encode(fileName, "UTF-8");
            }
            else
            {
                fileName = new String(fileName.getBytes("UTF-8"), "ISO8859-1");
            }
        }
        catch (Exception e)
        {
            logger.error("字符串编码转码失败", e);
        }
        return fileName;
    }
}
